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ALMA Measures Superheated Dust in Extreme Early-Universe Galaxy

New Band 9 observations of MACS0416_Y1 reveal 90 K dust that could explain why some young galaxies look dust-rich.

Overview

  • The galaxy MACS0416_Y1, seen at redshift 8.3 roughly 600 million years after the Big Bang, lies behind the MACS0416 cluster and its light has traveled more than 13 billion years.
  • ALMA’s Band 9 detection at 0.44 millimeters shows dust glowing at about 90 Kelvin, markedly warmer than in comparable distant systems.
  • Y1 is forming stars at over 180 solar masses per year, far above the Milky Way’s pace, indicating a brief, intense burst of growth.
  • JWST imaging helped pinpoint and characterize the source, while ALMA provided the temperature-sensitive measurement of the dust emission.
  • The peer-reviewed study in Monthly Notices of the Royal Astronomical Society proposes that small amounts of warm dust can mimic large dust masses, and the team plans high-resolution ALMA follow-up and searches for similar galaxies.